78919399 has 4 divisors (see below), whose sum is σ = 84990136. Its totient is φ = 72848664.

The previous prime is 78919387. The next prime is 78919429. The reversal of 78919399 is 99391987.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78919399 - 2⁹ = 78918887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78919339) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3035349 + ... + 3035374.

It is an arithmetic number, because the mean of its divisors is an integer number (21247534).

Almost surely, 2^78919399 is an apocalyptic number.

78919399 is a deficient number, since it is larger than the sum of its proper divisors (6070737).

78919399 is a wasteful number, since it uses less digits than its factorization.

78919399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6070736.

The product of its digits is 1102248, while the sum is 55.

The square root of 78919399 is about 8883.6590997179. The cubic root of 78919399 is about 428.9380664519.

The spelling of 78919399 in words is "seventy-eight million, nine hundred nineteen thousand, three hundred ninety-nine".